But in recent years, warming has lagged. So, where has the missing heat gone?

For climate sceptics, the answer is clear. Either the computer models used to project temperature rise are flawed, or man-made global warming is just a green scam, they say.

The report of the Intergovernmental Panel on Climate Change (IPCC) will confirm warming has recently slowed.

The document, being debated line-by-line in Stockholm, is the first volume of a vast trilogy that will be released by the Nobel-winning group over the coming months, and only its fifth overview in a quarter of a century.

Over the past 50 years, the mean global temperature rise was 0.12 degrees Celsius (0.2 degrees Fahrenheit) per decade, slowing to an average 0.05 C (0.09 F) per decade over the past 15 years.

Half of the slowdown could be attributed to volcanic eruptions, whose particles reflect sunlight, and a bigger-than expected drop in heat from the Sun's changing activity cycle, said a summary of the report.

The other half is attributed to a "cooling contribution from internal variability".

Laurent Terray with the French computer modelling agency Cerfacs said the term is used to explain a shift in the way heat is distributed between land, sea and air.

Still unclear is what causes the variation or determines its duration.

"We know that this kind of episode, of a decadal length or thereabouts, can occur once or twice a century," said Terray.

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"The recent slowdown in temperature increases isn't unprecedented, and should be seen as a 'speed bump' on the way to a warmer world."

Denialists will use whatever information they can find to bolster their world view that climate science is a left wing conspiracy (see antigoracle :) It remains to find good policies that can reduce our GHG footprint so that the climate for our children remains hospitable. On that, at least, the left and right should find common ground.

So lets see if @Anti's "Chicken" logic makes sense; He would need to show,

We don't know enough about the climate system, so there could have been some magical climate force that did cause a previous spike, just like today's

CO2 is not causing the current warming, even though they can't find an alternative explanation (and this is presumably supported by the fact that magical, invisible past spikes in warming do, in fact, maybe-exist).

CO2 would not cause any warming, even though our understanding of physics, the atmosphere, and evidence of past climates all show definitively that it would.

The last point is something the deniers do not seem to get. CO2 is a measured and know greenhouse gas, it's chemistry and physics properties are well known. There is no magic in global warming theory or observation. So what *appears* to be flattening of temperature rise over the past 15 years, IMHO is BS and a distraction from the future calamity of AGW!

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